diff --git a/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence.go b/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence.go
new file mode 100644
index 00000000..c5f13249
--- /dev/null
+++ b/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence.go	
@@ -0,0 +1,12 @@
+package leetcode
+
+import "strings"
+
+func isPrefixOfWord(sentence string, searchWord string) int {
+	for i, v := range strings.Split(sentence, " ") {
+		if strings.HasPrefix(v, searchWord) {
+			return i + 1
+		}
+	}
+	return -1
+}
diff --git a/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence_test.go b/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence_test.go
new file mode 100644
index 00000000..22607f7c
--- /dev/null
+++ b/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence_test.go	
@@ -0,0 +1,64 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question1455 struct {
+	para1455
+	ans1455
+}
+
+// para 是参数
+// one 代表第一个参数
+type para1455 struct {
+	sentence   string
+	searchWord string
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans1455 struct {
+	one int
+}
+
+func Test_Problem1455(t *testing.T) {
+
+	qs := []question1455{
+
+		question1455{
+			para1455{"i love eating burger", "burg"},
+			ans1455{4},
+		},
+
+		question1455{
+			para1455{"this problem is an easy problem", "pro"},
+			ans1455{2},
+		},
+
+		question1455{
+			para1455{"i am tired", "you"},
+			ans1455{-1},
+		},
+
+		question1455{
+			para1455{"i use triple pillow", "pill"},
+			ans1455{4},
+		},
+
+		question1455{
+			para1455{"hello from the other side", "they"},
+			ans1455{-1},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 1455------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans1455, q.para1455
+		fmt.Printf("【input】:%v      ", p)
+		fmt.Printf("【output】:%v      \n", isPrefixOfWord(p.sentence, p.searchWord))
+	}
+	fmt.Printf("\n\n\n")
+}
diff --git a/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/README.md b/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/README.md
new file mode 100644
index 00000000..c8081e82
--- /dev/null
+++ b/leetcode/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence/README.md
@@ -0,0 +1,98 @@
+# [1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence](https://leetcode.com/problems/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence/)
+
+
+## 题目
+
+Given a `sentence` that consists of some words separated by a **single space**, and a `searchWord`.
+
+You have to check if `searchWord` is a prefix of any word in `sentence`.
+
+Return *the index of the word* in `sentence` where `searchWord` is a prefix of this word (**1-indexed**).
+
+If `searchWord` is a prefix of more than one word, return the index of the first word **(minimum index)**. If there is no such word return **-1**.
+
+A **prefix** of a string `S` is any leading contiguous substring of `S`.
+
+**Example 1**:
+
+```
+Input: sentence = "i love eating burger", searchWord = "burg"
+Output: 4
+Explanation: "burg" is prefix of "burger" which is the 4th word in the sentence.
+
+```
+
+**Example 2**:
+
+```
+Input: sentence = "this problem is an easy problem", searchWord = "pro"
+Output: 2
+Explanation: "pro" is prefix of "problem" which is the 2nd and the 6th word in the sentence, but we return 2 as it's the minimal index.
+
+```
+
+**Example 3**:
+
+```
+Input: sentence = "i am tired", searchWord = "you"
+Output: -1
+Explanation: "you" is not a prefix of any word in the sentence.
+
+```
+
+**Example 4**:
+
+```
+Input: sentence = "i use triple pillow", searchWord = "pill"
+Output: 4
+
+```
+
+**Example 5**:
+
+```
+Input: sentence = "hello from the other side", searchWord = "they"
+Output: -1
+
+```
+
+**Constraints**:
+
+- `1 <= sentence.length <= 100`
+- `1 <= searchWord.length <= 10`
+- `sentence` consists of lowercase English letters and spaces.
+- `searchWord` consists of lowercase English letters.
+
+## 题目大意
+
+给你一个字符串 sentence 作为句子并指定检索词为 searchWord ，其中句子由若干用 单个空格 分隔的单词组成。请你检查检索词 searchWord 是否为句子 sentence 中任意单词的前缀。
+
+- 如果 searchWord 是某一个单词的前缀，则返回句子 sentence 中该单词所对应的下标（下标从 1 开始）。
+- 如果 searchWord 是多个单词的前缀，则返回匹配的第一个单词的下标（最小下标）。
+- 如果 searchWord 不是任何单词的前缀，则返回 -1 。
+
+字符串 S 的 「前缀」是 S 的任何前导连续子字符串。
+
+## 解题思路
+
+- 给出 2 个字符串，一个是匹配串，另外一个是句子。在句子里面查找带匹配串前缀的单词，并返回第一个匹配单词的下标。
+- 简单题。按照题意，扫描一遍句子，一次匹配即可。
+
+## 代码
+
+```go
+
+package leetcode
+
+import "strings"
+
+func isPrefixOfWord(sentence string, searchWord string) int {
+	for i, v := range strings.Split(sentence, " ") {
+		if strings.HasPrefix(v, searchWord) {
+			return i + 1
+		}
+	}
+	return -1
+}
+
+```
\ No newline at end of file
diff --git a/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/1464. Maximum Product of Two Elements in an Array.go b/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/1464. Maximum Product of Two Elements in an Array.go
new file mode 100644
index 00000000..a88bccb1
--- /dev/null
+++ b/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/1464. Maximum Product of Two Elements in an Array.go	
@@ -0,0 +1,14 @@
+package leetcode
+
+func maxProduct(nums []int) int {
+	max1, max2 := 0, 0
+	for _, num := range nums {
+		if num >= max1 {
+			max2 = max1
+			max1 = num
+		} else if num <= max1 && num >= max2 {
+			max2 = num
+		}
+	}
+	return (max1 - 1) * (max2 - 1)
+}
diff --git a/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/1464. Maximum Product of Two Elements in an Array_test.go b/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/1464. Maximum Product of Two Elements in an Array_test.go
new file mode 100644
index 00000000..06c9821f
--- /dev/null
+++ b/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/1464. Maximum Product of Two Elements in an Array_test.go	
@@ -0,0 +1,58 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question1464 struct {
+	para1464
+	ans1464
+}
+
+// para 是参数
+// one 代表第一个参数
+type para1464 struct {
+	nums []int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans1464 struct {
+	one int
+}
+
+func Test_Problem1464(t *testing.T) {
+
+	qs := []question1464{
+
+		question1464{
+			para1464{[]int{3, 4, 5, 2}},
+			ans1464{12},
+		},
+
+		question1464{
+			para1464{[]int{1, 5, 4, 5}},
+			ans1464{16},
+		},
+
+		question1464{
+			para1464{[]int{3, 7}},
+			ans1464{12},
+		},
+
+		question1464{
+			para1464{[]int{1}},
+			ans1464{0},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 1464------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans1464, q.para1464
+		fmt.Printf("【input】:%v      ", p)
+		fmt.Printf("【output】:%v      \n", maxProduct(p.nums))
+	}
+	fmt.Printf("\n\n\n")
+}
diff --git a/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/README.md b/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/README.md
new file mode 100644
index 00000000..04dbf134
--- /dev/null
+++ b/leetcode/1464.Maximum-Product-of-Two-Elements-in-an-Array/README.md
@@ -0,0 +1,66 @@
+# [1464. Maximum Product of Two Elements in an Array](https://leetcode.com/problems/maximum-product-of-two-elements-in-an-array/)
+
+
+## 题目
+
+Given the array of integers `nums`, you will choose two different indices `i` and `j` of that array. Return the maximum value of `(nums[i]-1)*(nums[j]-1)`.
+
+**Example 1**:
+
+```
+Input: nums = [3,4,5,2]
+Output: 12 
+Explanation: If you choose the indices i=1 and j=2 (indexed from 0), you will get the maximum value, that is, (nums[1]-1)*(nums[2]-1) = (4-1)*(5-1) = 3*4 = 12. 
+
+```
+
+**Example 2**:
+
+```
+Input: nums = [1,5,4,5]
+Output: 16
+Explanation: Choosing the indices i=1 and j=3 (indexed from 0), you will get the maximum value of (5-1)*(5-1) = 16.
+
+```
+
+**Example 3**:
+
+```
+Input: nums = [3,7]
+Output: 12
+
+```
+
+**Constraints**:
+
+- `2 <= nums.length <= 500`
+- `1 <= nums[i] <= 10^3`
+
+## 题目大意
+
+给你一个整数数组 nums，请你选择数组的两个不同下标 i 和 j，使 (nums[i]-1)*(nums[j]-1) 取得最大值。请你计算并返回该式的最大值。
+
+## 解题思路
+
+- 简单题。循环一次，按照题意动态维护 2 个最大值，从而也使得 `(nums[i]-1)*(nums[j]-1)` 能取到最大值。
+
+## 代码
+
+```go
+
+package leetcode
+
+func maxProduct(nums []int) int {
+	max1, max2 := 0, 0
+	for _, num := range nums {
+		if num >= max1 {
+			max2 = max1
+			max1 = num
+		} else if num <= max1 && num >= max2 {
+			max2 = num
+		}
+	}
+	return (max1 - 1) * (max2 - 1)
+}
+
+```
\ No newline at end of file
diff --git a/leetcode/1470.Shuffle-the-Array/1470. Shuffle the Array.go b/leetcode/1470.Shuffle-the-Array/1470. Shuffle the Array.go
new file mode 100644
index 00000000..fef82041
--- /dev/null
+++ b/leetcode/1470.Shuffle-the-Array/1470. Shuffle the Array.go	
@@ -0,0 +1,10 @@
+package leetcode
+
+func shuffle(nums []int, n int) []int {
+	result := make([]int, 0)
+	for i := 0; i < n; i++ {
+		result = append(result, nums[i])
+		result = append(result, nums[n+i])
+	}
+	return result
+}
diff --git a/leetcode/1470.Shuffle-the-Array/1470. Shuffle the Array_test.go b/leetcode/1470.Shuffle-the-Array/1470. Shuffle the Array_test.go
new file mode 100644
index 00000000..212ecef9
--- /dev/null
+++ b/leetcode/1470.Shuffle-the-Array/1470. Shuffle the Array_test.go	
@@ -0,0 +1,53 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question1470 struct {
+	para1470
+	ans1470
+}
+
+// para 是参数
+// one 代表第一个参数
+type para1470 struct {
+	nums []int
+	n    int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans1470 struct {
+	one []int
+}
+
+func Test_Problem1470(t *testing.T) {
+
+	qs := []question1470{
+
+		question1470{
+			para1470{[]int{2, 5, 1, 3, 4, 7}, 3},
+			ans1470{[]int{2, 3, 5, 4, 1, 7}},
+		},
+
+		question1470{
+			para1470{[]int{1, 2, 3, 4, 4, 3, 2, 1}, 4},
+			ans1470{[]int{1, 4, 2, 3, 3, 2, 4, 1}},
+		},
+
+		question1470{
+			para1470{[]int{1, 1, 2, 2}, 2},
+			ans1470{[]int{1, 2, 1, 2}},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 1470------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans1470, q.para1470
+		fmt.Printf("【input】:%v      【output】:%v      \n", p, shuffle(p.nums, p.n))
+	}
+	fmt.Printf("\n\n\n")
+}
diff --git a/leetcode/1470.Shuffle-the-Array/README.md b/leetcode/1470.Shuffle-the-Array/README.md
new file mode 100644
index 00000000..961d200c
--- /dev/null
+++ b/leetcode/1470.Shuffle-the-Array/README.md
@@ -0,0 +1,64 @@
+# [1470. Shuffle the Array](https://leetcode.com/problems/shuffle-the-array/)
+
+## 题目
+
+Given the array `nums` consisting of `2n` elements in the form `[x1,x2,...,xn,y1,y2,...,yn]`.
+
+*Return the array in the form* `[x1,y1,x2,y2,...,xn,yn]`.
+
+**Example 1**:
+
+```
+Input: nums = [2,5,1,3,4,7], n = 3
+Output: [2,3,5,4,1,7] 
+Explanation: Since x1=2, x2=5, x3=1, y1=3, y2=4, y3=7 then the answer is [2,3,5,4,1,7].
+
+```
+
+**Example 2**:
+
+```
+Input: nums = [1,2,3,4,4,3,2,1], n = 4
+Output: [1,4,2,3,3,2,4,1]
+
+```
+
+**Example 3**:
+
+```
+Input: nums = [1,1,2,2], n = 2
+Output: [1,2,1,2]
+
+```
+
+**Constraints**:
+
+- `1 <= n <= 500`
+- `nums.length == 2n`
+- `1 <= nums[i] <= 10^3`
+
+## 题目大意
+
+给你一个数组 nums ，数组中有 2n 个元素，按 [x1,x2,...,xn,y1,y2,...,yn] 的格式排列。请你将数组按 [x1,y1,x2,y2,...,xn,yn] 格式重新排列，返回重排后的数组。
+
+## 解题思路
+
+- 给定一个 2n 的数组，把后 n 个元素插空放到前 n 个元素里面。输出最终完成的数组。
+- 简单题，按照题意插空即可。
+
+## 代码
+
+```go
+
+package leetcode
+
+func shuffle(nums []int, n int) []int {
+	result := make([]int, 0)
+	for i := 0; i < n; i++ {
+		result = append(result, nums[i])
+		result = append(result, nums[n+i])
+	}
+	return result
+}
+
+```
\ No newline at end of file
diff --git a/website/content/ChapterFour/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence.md b/website/content/ChapterFour/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence.md
new file mode 100644
index 00000000..c8081e82
--- /dev/null
+++ b/website/content/ChapterFour/1455.Check-If-a-Word-Occurs-As-a-Prefix-of-Any-Word-in-a-Sentence.md
@@ -0,0 +1,98 @@
+# [1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence](https://leetcode.com/problems/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence/)
+
+
+## 题目
+
+Given a `sentence` that consists of some words separated by a **single space**, and a `searchWord`.
+
+You have to check if `searchWord` is a prefix of any word in `sentence`.
+
+Return *the index of the word* in `sentence` where `searchWord` is a prefix of this word (**1-indexed**).
+
+If `searchWord` is a prefix of more than one word, return the index of the first word **(minimum index)**. If there is no such word return **-1**.
+
+A **prefix** of a string `S` is any leading contiguous substring of `S`.
+
+**Example 1**:
+
+```
+Input: sentence = "i love eating burger", searchWord = "burg"
+Output: 4
+Explanation: "burg" is prefix of "burger" which is the 4th word in the sentence.
+
+```
+
+**Example 2**:
+
+```
+Input: sentence = "this problem is an easy problem", searchWord = "pro"
+Output: 2
+Explanation: "pro" is prefix of "problem" which is the 2nd and the 6th word in the sentence, but we return 2 as it's the minimal index.
+
+```
+
+**Example 3**:
+
+```
+Input: sentence = "i am tired", searchWord = "you"
+Output: -1
+Explanation: "you" is not a prefix of any word in the sentence.
+
+```
+
+**Example 4**:
+
+```
+Input: sentence = "i use triple pillow", searchWord = "pill"
+Output: 4
+
+```
+
+**Example 5**:
+
+```
+Input: sentence = "hello from the other side", searchWord = "they"
+Output: -1
+
+```
+
+**Constraints**:
+
+- `1 <= sentence.length <= 100`
+- `1 <= searchWord.length <= 10`
+- `sentence` consists of lowercase English letters and spaces.
+- `searchWord` consists of lowercase English letters.
+
+## 题目大意
+
+给你一个字符串 sentence 作为句子并指定检索词为 searchWord ，其中句子由若干用 单个空格 分隔的单词组成。请你检查检索词 searchWord 是否为句子 sentence 中任意单词的前缀。
+
+- 如果 searchWord 是某一个单词的前缀，则返回句子 sentence 中该单词所对应的下标（下标从 1 开始）。
+- 如果 searchWord 是多个单词的前缀，则返回匹配的第一个单词的下标（最小下标）。
+- 如果 searchWord 不是任何单词的前缀，则返回 -1 。
+
+字符串 S 的 「前缀」是 S 的任何前导连续子字符串。
+
+## 解题思路
+
+- 给出 2 个字符串，一个是匹配串，另外一个是句子。在句子里面查找带匹配串前缀的单词，并返回第一个匹配单词的下标。
+- 简单题。按照题意，扫描一遍句子，一次匹配即可。
+
+## 代码
+
+```go
+
+package leetcode
+
+import "strings"
+
+func isPrefixOfWord(sentence string, searchWord string) int {
+	for i, v := range strings.Split(sentence, " ") {
+		if strings.HasPrefix(v, searchWord) {
+			return i + 1
+		}
+	}
+	return -1
+}
+
+```
\ No newline at end of file
diff --git a/website/content/ChapterFour/1464.Maximum-Product-of-Two-Elements-in-an-Array.md b/website/content/ChapterFour/1464.Maximum-Product-of-Two-Elements-in-an-Array.md
new file mode 100644
index 00000000..04dbf134
--- /dev/null
+++ b/website/content/ChapterFour/1464.Maximum-Product-of-Two-Elements-in-an-Array.md
@@ -0,0 +1,66 @@
+# [1464. Maximum Product of Two Elements in an Array](https://leetcode.com/problems/maximum-product-of-two-elements-in-an-array/)
+
+
+## 题目
+
+Given the array of integers `nums`, you will choose two different indices `i` and `j` of that array. Return the maximum value of `(nums[i]-1)*(nums[j]-1)`.
+
+**Example 1**:
+
+```
+Input: nums = [3,4,5,2]
+Output: 12 
+Explanation: If you choose the indices i=1 and j=2 (indexed from 0), you will get the maximum value, that is, (nums[1]-1)*(nums[2]-1) = (4-1)*(5-1) = 3*4 = 12. 
+
+```
+
+**Example 2**:
+
+```
+Input: nums = [1,5,4,5]
+Output: 16
+Explanation: Choosing the indices i=1 and j=3 (indexed from 0), you will get the maximum value of (5-1)*(5-1) = 16.
+
+```
+
+**Example 3**:
+
+```
+Input: nums = [3,7]
+Output: 12
+
+```
+
+**Constraints**:
+
+- `2 <= nums.length <= 500`
+- `1 <= nums[i] <= 10^3`
+
+## 题目大意
+
+给你一个整数数组 nums，请你选择数组的两个不同下标 i 和 j，使 (nums[i]-1)*(nums[j]-1) 取得最大值。请你计算并返回该式的最大值。
+
+## 解题思路
+
+- 简单题。循环一次，按照题意动态维护 2 个最大值，从而也使得 `(nums[i]-1)*(nums[j]-1)` 能取到最大值。
+
+## 代码
+
+```go
+
+package leetcode
+
+func maxProduct(nums []int) int {
+	max1, max2 := 0, 0
+	for _, num := range nums {
+		if num >= max1 {
+			max2 = max1
+			max1 = num
+		} else if num <= max1 && num >= max2 {
+			max2 = num
+		}
+	}
+	return (max1 - 1) * (max2 - 1)
+}
+
+```
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diff --git a/website/content/ChapterFour/1470.Shuffle-the-Array.md b/website/content/ChapterFour/1470.Shuffle-the-Array.md
new file mode 100644
index 00000000..961d200c
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@@ -0,0 +1,64 @@
+# [1470. Shuffle the Array](https://leetcode.com/problems/shuffle-the-array/)
+
+## 题目
+
+Given the array `nums` consisting of `2n` elements in the form `[x1,x2,...,xn,y1,y2,...,yn]`.
+
+*Return the array in the form* `[x1,y1,x2,y2,...,xn,yn]`.
+
+**Example 1**:
+
+```
+Input: nums = [2,5,1,3,4,7], n = 3
+Output: [2,3,5,4,1,7] 
+Explanation: Since x1=2, x2=5, x3=1, y1=3, y2=4, y3=7 then the answer is [2,3,5,4,1,7].
+
+```
+
+**Example 2**:
+
+```
+Input: nums = [1,2,3,4,4,3,2,1], n = 4
+Output: [1,4,2,3,3,2,4,1]
+
+```
+
+**Example 3**:
+
+```
+Input: nums = [1,1,2,2], n = 2
+Output: [1,2,1,2]
+
+```
+
+**Constraints**:
+
+- `1 <= n <= 500`
+- `nums.length == 2n`
+- `1 <= nums[i] <= 10^3`
+
+## 题目大意
+
+给你一个数组 nums ，数组中有 2n 个元素，按 [x1,x2,...,xn,y1,y2,...,yn] 的格式排列。请你将数组按 [x1,y1,x2,y2,...,xn,yn] 格式重新排列，返回重排后的数组。
+
+## 解题思路
+
+- 给定一个 2n 的数组，把后 n 个元素插空放到前 n 个元素里面。输出最终完成的数组。
+- 简单题，按照题意插空即可。
+
+## 代码
+
+```go
+
+package leetcode
+
+func shuffle(nums []int, n int) []int {
+	result := make([]int, 0)
+	for i := 0; i < n; i++ {
+		result = append(result, nums[i])
+		result = append(result, nums[n+i])
+	}
+	return result
+}
+
+```
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